Eyes wide open—an atypical presentation of Miller Fisher syndrome (MFS): case report

Abstract

Background Parinaud’s syndrome, also known as dorsal midbrain syndrome, is characterized by a combination of signs, including upgaze palsy, convergence–retraction nystagmus, eyelid retraction and pupillary dissociation. It is caused by pretectal or tegmental lesions of upper brainstem. Miller Fisher syndrome, characterized by the triad of ataxia, areflexia and ophthalmoplegia, has rarely been reported to present as Parinaud’s syndrome in adults. To our knowledge, this clinical manifestation has not been previously described in children. Case presentation A previously healthy 13-year-old girl presented with blurred vision and diplopia, 10 days after a viral infection. Initial examination revealed incomplete Parinaud’s syndrome, while rest of neurological examination was normal. Brain imaging (MRI, MRA) did not reveal any abnormal findings and CSF findings were also normal. During the first days after admission she gradually deteriorated, showing complete external ophthalmoplegia, unsteady gait, and absent deep tendon reflexes of lower limbs with normal muscle power. With the clinical suspicion of Miller Fisher syndrome IVIG was administered, leading to subsequent resolution of her symptoms. AntiGQ1b and antiGD1b antibodies came back positive confirming diagnosis. On 1 month follow-up, neurological examination revealed diplopia in left gaze, and a second dose of IVIG was administered with good response. She remains asymptomatic 1 year from disease onset. Conclusions Miller Fisher syndrome can rarely present as Parinaud’s syndrome in adults. Herein we described the first pediatric patient with similar clinical presentation. As the typical semiology of ataxia and areflexia may not be present initially, high index of suspicion is required to recognise and treat those patients promptly. Serological detection of anti-ganglioside antibodies, such as anti-GQ1b and anti-GD1b, may help confirm diagnosis.